SURG-08. RESECTION OF CONTRAST ENHANCING TISSUE PROLONGS OVERALL SURVIVAL IN GLIOMAS – SECONDARY ENDPOINT ANALYSIS OF A RANDOMIZED CONTROLLED TRIAL ON INTRAOPERATIVE MRI USE

Abstract

BACKGROUND: There is a lack of high-class evidence to promote surgical treatment of gliomas. In a previosly published randomized controlled trial (RCT) the use of an intraoperative MRI (iMRI) led to improved rates of complete tumor removal (GTR) in glioma surgery. In this study, GTR was associated with longer progression-free survival. Here, we report on the overall survival (OS) of trial participants as a prespecified secondary study endpoint. METHODS: In an RCT (registered with ClinicalTrials.gov, number NCT01394692), we enrolled adults (≥18 years) with contrast enhancing gliomas amenable to radiologically complete resection who presented to our institution. We randomly assigned patients (1:1) to undergo iMRIguided surgery or conventional microsurgery (control group). Surgeons and patients were unmasked to treatment group allocation, but an independent neuroradiologist was masked during analysis of all pre- and postoperative imaging data. Analysis was done per protocol. At 5-year follow-up, we performed an analysis of OS data. RESULTS: We enrolled 58 patients with contrast enhancing gliomas between Oct 1, 2007, and July 1, 2010. 24 (83%) of 29 patients randomly allocated to the iMRI group and 21 (72.4%) of 29 controls were eligible for analysis of OS. Median OS was 18.9 months. The use of iMRI itself did not affect outcome (560 vs. 624 days, p=0.53). GTR (724 vs. 437 days, p=0.024), MGMT promotor methylation status (641 vs. 500 days, p=0.026) and tumor recurrence (576 vs. 560 days, p=0.038) were associated with OS in a multivariate analysis. Also for the subgroup of patients with IDH1-R132H-wt untreated glioblastomas, a multivariate analyis identified MGMT promotor methylation status (HR 1.81, p=0.036) and GTR (HR 2.42, p=0.024) as parameters independently associated with OS. CONCLUSIONS: Our data provide evidence that GTR is an independent prognostic factor in high grade gliomas. Intraoperative resection control is warranted to optimize surgical treatment.